Radio Frequency Identification (RFID) uses a smart tag capable of transmitting data by radio. The basic RFID system consists of 3 components:
An antenna or coil
A transceiver (with decoder)
A transponder tag (called a RFID tag) electronically programmed with unique information
The basic feature of a RFID tag is to detect the interrogation field or transmission in order to affect a response for data transfer. The main components in a RFID tag circuitry essentially comprises of the following elements:
The antenna and radio frequency receiver and transmission circuit
Micro-processing circuit for control and data management purpose.
Memory, appropriate to data carrier and functionality needs.
There are basically 3 types of RFID transponders that are most widely used in the world. They are (a) contactless cards, (b) contactless tickets and (c) smart labels.
A smart RFID label has a transponder device with a programmable microchip and an antenna. Data can be read or written with a reader device, without a direct line of sight. Transponders embedded inside paper labels (“RFID labels”) assist businesses in product identification, control, tracking and security and are used in a wide variety of applications including:                Airline baggage management        Library systems and rental services        Retail, including electronic article surveillance        Supply chain logistics        Postal and parcel tracking services        Personnel identification and ticketing        Waste management        Vehicle identification        Fraud control and identification        
Methods of manufacture of RFID labels are known. For example, U.S. Pat. No. 6,451,154 describes a method of making RFID labels comprising: (a) providing a plurality of RFID inlets, each including a chip (and antenna), on a first web; (b) covering the RFID inlets with a second web to provide a composite web; (c) providing pressure sensitive adhesive on a portion of one of the webs that will be an exterior portion of a label once ultimately formed; (d) verifying the functionality of, or programming, the chips prior to formation of the composite web; and, (e) acting on the composite web so as to provide the composite web into labels having a top face, and a bottom face with pressure sensitive adhesive. Step (b) is practiced by laminating the first and second webs by passing them between laminating rolls without harming the RFID inlets by providing a recess in at least one of the laminating rolls in alignment with the RFID inlets. The method may further comprise (f) imaging variable indicia on the top face. High speed practice of the method is possible; that is (a)-(e) may be practiced at a rate of at least about 100 feet per minute (e.g. up to about 300 ft./min.) and also typically (f) is practiced after (e).
The method described by U.S. Pat. No. 6,451,154 uses conventional web moving equipment and is designed for high volume RFID label production.
An alternative process of manufacturing RFID labels is to convert RFID tag to RFID labels in batches. This batch process is meant for specific batches of labels, as requested by the customer e.g. shipping labels related to say, one particular container or even a few containers for a specific shipment or shipping labels for one particular flight. Such a specific batch conversion of RFID tags to RFID labels is unlike the invention described in U.S. Pat. No. 6,451,154. In the batch conversion of RFID labels, the RFID tags and label liner are fed together at one point to convert the RFID tags into RFID labels. Each RFID tag must be accurately embedded onto each paper label and then encoded and have the bar codes printed in the same process. Unlike the invention described by U.S. Pat. No. 6,451,154, the RFID tags are embedded one by one onto a liner of labels spaced apart at regular intervals or “pitch” so that each RFID tag is embedded onto a label.
Irrespective of whether it is a production of a high volume RFID labels or production of a batch of RFID labels, practitioners of the science of making RFID labels are aware that there is a “sweet spot” for embedding the RFID tag as well as placement of printer/encoder within the label.
In the batch process of RFID tag to RFID label conversion, the making of RFID labels is made difficult due to the different sizes of each batch of labels, again due to specific customer requirements. The current practice used in batch conversion of RFID tags to RFID labels is a manual method of “meeting, matching and sticking”. Much set up time is spent to ensure the process of RFID tag to RFID label conversion is accurately carried out for one batch. When the label size is changed for the next batch of RFID labels, set up time is again incurred. The current manual method is not only time consuming and results in high wastage. Furthermore, once the “meeting, matching and sticking” has been carried out, there is no assurance that the calibrations remains the same throughout the entire batch. There is therefore the possibility of the RFID tags not embedded correctly onto the RFID labels in the “sweet spot” resulting in more defective RFID labels. The next batch of RFID tag to RFID label conversion must again undergo the “meeting, matching and sticking” manual method, even though the size of the labels may be the same. Thus the current method of “meeting, matching and sticking” to convert RFID tags to RFID labels not only result in high wastage and man hour costs, but is also complicated, and not user friendly.
The problems associated with batch conversion of current RFID tag to RFID label are as follows:
High wastage of material;
Too many processes in converting RFID tag to RFID label;
Micro-processing circuit may be damaged during conversion;
Problem of Pitch control i.e. distance between RFID tag and label;
If the elements of a RFID tag are not converted accurately, a high level of wastage would result.
This invention is concerned with addressing the problems arising from pitch control faced in the current RFID tag to RFID label conversion batch process. This problem arises as RFID tags have to be embedded in paper labels and is exacerbated when for each batch, the label size (or dimensions) vary, these label sizes being specified by the end users. In current methods of embedding RFID tag onto paper labels to produce RFID labels, difficulty lies in that pitch control is always variable according to customer requirements i.e. the size of the label varies and therefore the size of paper labels of each batch may vary.
Current methods of batch embedding a RFID tag onto a paper label is carried by a procedure of “meet, match and stick” which results in high material wastage and additional man hours. This is primarily because the speed of dispensing of the RFID tags which comes in a roll has to be matched to the speed of dispensing of the paper labels which also comes in a roll such that one RFID tag is embedded onto one paper label at the correct location in the paper label as the liner (which is made up of the eventual labels) rolls out. Since each batch of RFID labels is different in dimensions, a trial and error procedure has to be adopted for each batch. Even in the course of running a batch to convert RFID tags to RFID labels, there would be some spoilage due to inaccurate embedding of the RFID tags onto the labels. Consequently, this has resulted in much wastage and high man hour costs.
The inventors have researched into the problem of embedding a RFID tag accurately onto a paper label for batch conversion of RIFD tags to RFID labels. The inventors have proposed a method for accurate embedding of RFID tags onto paper labels through improved pitch control by using sensors to detect certain markers made on the label. The invention will ensure lower costs of labor/man-hour, improved efficiency of production/conversion process and reduced wastage during tag-label conversion. More fundamentally, the invention would result in a significant reduction of the costs of RFID labels, thus making RFID labels less costly in use, thereby making RFID labels more attractive to use in manufacturing, logistics and other hostile environment where bar code labels may not perform as well